With the substantial completion of decoding the human genome in 2001 as a turning point, the focus of studies in the field of biotechnology research is shifting from genomic to proteomic research in which pursuit is made about when, where and how genetic information possessed by individual living things is expressed in making proteins, and how these produced proteins function in the cells of individual organisms in cooperation with other proteins. The function of most proteins is related to their interaction with other biomolecules, so that one of the momentous subjects in the study of proteomes is the interaction between the proteins themselves or with other biomolecules. Further, in the researches on the interaction of biomolecules, it is imperative to know the equilibrium constant which indicates the strength of the intermolecular bond in the equilibrium state and the rate constant which indicates the velocity until equilibrium is reached. Biosensors are among the devices available for examining the interaction represented by such equilibrium constant and rate constant of biomolecules. Biosensors make use of the phenomenon of surface plasmon resonance. There are also known biosensors using a Dual Polarization Interferometer.
In this type of sensor device, the number of the sensors that can be measured simultaneously is considered to be 4 or so. For the efficient analysis of the interaction of the objective biomolecules, an apparatus allowing simultaneous measurement of a greater number of sensors is required.
Simultaneous measurement of multiple sensors calls for the improvements of various factors such as miniaturization and greater compactness of the sensors, reduction of the amount of the specimen required, shortening of measuring time, miniaturization of the apparatus itself, and miniaturization of the sensor and flow systems. Studies for miniaturization of measuring devices are being made enthusiastically in recent years, and this field of study is referred to as μTAS (Micro Total Analysis System) or Lab-On-Chip in the art.
In the field of μTAS, particularly the micro-flow cells and micro-valves which handle fluids, are called microfluidic devices. Combinations of such microfluidic devices and multiple sensors have been proposed as a microchip in JP-A-2002-243734 and an integrated reactor in JP-A-2002-357607. The microchip disclosed in JP-A-2002-243734 comprises a substrate to which the organic high molecules are fixated as spots or strip-wise, and another substrate having a recessed portion that provides a micro channel, said both substrates being joined together. In the integrated reactor disclosed in JP-A-2002-357607, a groove is formed in a glass or silicon substrate to form a capillary, and DNA is bound to its surface by using the lithographic techniques.